Chloride compounds have been recognized for some time as serious poisons to many catalytic reactions. Such chloride contamination, however, previously has been from sources other than the hydrocarbon feed to plants used to make products such as hydrogen and ammonia. Several factors have recently required the use of heavier, normally liquid type hydrocarbon feeds to these plants which previously were designed for the most part to use normally gaseous natural gas type feeds consisting primarily of methane. Such natural gas feeds contain little, if any, chloride compounds. Further, due to the serious shortage of natural gas, used for heating and commercial installations, synthetic natural gas plants are now in the design or construction stage as replacements for the dwindling natural gas supplies. These so called SNG (synthetic natural gas) plants are being designed to use primarily naphtha type hydrocarbon feeds which are converted in these plants to natural gas type fuel, consisting of high concentrations of methane. Many of these naphtha feeds contain relatively high levels of chloride compounds, as well as high levels of sulfur compounds, both of which, if not essentially completely removed, result in serious poisoning of all other catalysts in SNG plants. Further, many plants presently operating, such as those for making hydrogen and ammonia, were originally designed to use a natural gas feed and will have to be modified so that a heavier type feed stock can be used. It has been found that high surface area zinc oxide sulfur adsorbents have low capacity for removal of chlorides. This capacity is, in fact, in the range of from 0.25 to 1.0 wt. percent chloride retention of the entire adsorbent mass, based on chloride leakage or breakthrough of one part per million or less. Since these adsorbents are not regenerative, such a low chloride retention level is commercially unfeasible. Further, it has been found that chlorides in trace quantities in the feed stocks seriously reduce the sulfur retention capacity of the commercially available high surface area zinc oxide sulfur adsorbents. Therefore, chloride contaminants in the hydrogen treated feed stocks not only act as poisons for the downstream catalysts of SNG, hydrogen and ammonia plants, but act as poisons for the sulfur adsorbents used as a guard for such catalysts.